In August 2007, the USDA changed from calculating official
geneticevaluations quarterly to triannually in conjunction with
theschedule change for international evaluations. To offset
partof the delay in providing genetic information because of
thereduced frequency of official evaluations, industry
cooperatorsrequested that interim evaluations be initiated for
progeny-test(PT) bulls based on first-lactation records from PT
daughtersand their contemporaries that calved recently in
cooperatorherds. Alternatives for interim evaluations were studied
todetermine which would characterize genetic merit of PT bullsmost accurately. Four alternative Holstein data sources wereexamined based on maximum data interval (most recent 12 or 18mo of first calvings) and minimum number of PT daughters inherd (1 or 5). The highest correlation between
August 2006interim and official evaluations for milk yield was 0.980
forinterim evaluations based on the most recent 18 mo of firstcalvings from cooperator herds with 1 PT daughter. That highcorrelation confirmed that interim evaluations based on limiteddata could provide genetic estimates of value between officialevaluations. With the support of the Council on Dairy CattleBreeding, the USDA initiated 3 interim evaluations each yearwith release limited to PT bulls with 10 daughters and an increasein reliability since the most recent official evaluation.